Association between two types of vitamin D receptor gene polymorphism and bone status in premenopausal Japanese women

Polymorphisms in the vitamin D receptor (VDR) gene using ultrasound (US) bo ne mass and bone metabolic markers were investigated as potential genetic m arkers for osteoporosis in 126 premenopausal Japanese women aged 27.2 +/- 1 0.1 (mean +/- SD) years. The relationship between their VDR gene polymorphi sms and bone states was determined. VDR genotypes were based on the absence (B) or presence (b) of the Bsm I restriction site (B polymorphism), and AT G (the M allele) and ACG (the m allele) sequences at the translation initia tion site (M polymorphism). Genotype frequencies were 73.8%, bb; 24.6%, Bb; 1.6%, BE; 15.1%, MM; 51.6%, Mm and 33.3%, mm. The stiffness index of calca neal bone minerals measured by an US bone densitometer was significantly hi gher in the mm types (P < 0.05 versus MM) than in the Mm types (P < 0.01 ve rsus MM) and MM types. There was no significant difference between in B pol ymorphisms. Furthermore, bone mass was correlated with serum bone type alka line phosphatase (ALP) activity and urinary deoxypyridinoline concentration in M polymorphisms. Because the distribution of B polymorphisms in each M polymorphism genotype did not differ, M polymorphisms were affected indepen dently from B polymorphisms to bone mass or bone metabolic markers. No sign ificant difference was observed in nutritional intake and food consumption among genotypes. In the MM and Mm types, the bone mass was closely related to the frequency of milk intake during the periods of elementary and junior high school. In contrast, bone mass was not associated with nutritional in take or the frequency of past milk intake in B polymorphisms. Therefore, th e M polymorphism of the VDR gene is a stronger genetic indicator of osteopo rosis than the B polymorphism in premenopausal Japanese woman.